The present invention relates of a hip prosthesis structure, which is adapted to be easily fitted to the specific shape or geometrical characteristics of the patient coxo-femural articulation.
As is known in the case of fractures, arthritis and the like of the human hip or its articulated joint with the femur, there are conventionally used suitable hip prosthesis in order to provide the hip joint with renewed mobility.
Conventional hip prosthesis structures are usually made as a single piece, consisting of a stem from the top portion of which a coupling portion extends thereon there is applied a spherical head, provided for engaging in the femur acetabulum.
The thus constructed prosthesis, however, have the drawback that they can not be used for all of the patients, unless said prostheses are specifically adapted in size to the geometrical structure of the hip and femur of the patient.
In fact, these prostheses, though they have been tailored in a satisfactory way for a given patient, can not be adapted to other patients mainly because their coupling portions have a greater or smaller length than that suitable for providing a proper coxofemural articulation.
In these cases, as it should be apparent, the prosthesis head can not be properly fitted to the patient acetabulum therewith it should cooperate.
Sometimes, moreover, the patient has a so-called "varus" femur, that is having a rather anomalous shape, and for these femurs particular hip prostheses must be adopted in which the coupling portion has a specific preset orientation with respect to the stem.
In this connection, it should be moreover pointed out that the femur coupling portion is not perpendicular to the patient pelvis thereby a normal coupling portion is reversed at about 10.degree. with respect to the pelvis.
Known hip prostheses, on the other hand, are not designed to overcome this drawback and hence they cannot be adapted in a perfect way to the anatomic characteristics of a lot of patients.